[tomb]

 

Those of you that follow the ODAC may have learned to despise RMAA, but if used for direct comparison rather than absolute measurements, I don't think you can fault it:

If possible, could you run the same tests on an ODAC with and without the external PS and post the results? I think that many here including myself will be interested in your findings.

Well, if I had an ODAC - I would.  But I don't, so I can't.

  Even though we've had disagreements in the past, I would defer to purrin's measurements/experience using an ODAC with a linear-regulated external power supply (it might've been the iFi, I can't remember).  If my recollection is correct, he confirmed that there were differences.
 
There's also this:
 

  running off a dedicated USB PCI on my desktop without other devices connected, into either a B22 or QRV-08, and AD2000 or modded T50RP headphones, the ODAC is etched, bright, rough and harsh.  makes the BM DAC1 i recently sold after 6 years of enjoyment sound warm, smooth, and analog.  with the Doodlebug inserted, less bright/etched and more fleshed out.  more details and more natural sounding.  still not my cup of coffee, but the Doodlebug is an improvement in my rig.  
 
maybe my desktop USB power really sucks, or the implementation of the secret sauce Sabre is black magic.  either way, isolation and clean power brings improvements.
 
huge props to A_A and tomb.
 
from a build perspective, the pads are generous and require a little extra heat.  high quality board and a perfect first time SMD project. 

 
Granted that's a subjective opinion, but one from a very-experienced, high-end DIY-er.
 
The other thing to consider from an engineering perspective, is that it's logical and a conservative application.  It removes additional unknowns that have the potential to affect sound quality.  It's in the direction of better - with zero risk - except for a small investment.

 

[adydula]

"the guys in the white lab coats have determined DNR greater than 100 dB results in transparency under realistic conditions. And, if you want to adjust the volume in software, it’s best to have at least 110 dB DNR to keep the noise floor inaudible even if the downstream gain is left cranked way up. Anything beyond 110 dB is past the point of diminishing returns—it looks nice on paper but doesn’t help the sound quality......"
 
Fyi
A.

 

[tomb]

  "the guys in the white lab coats have determined DNR greater than 100 dB results in transparency under realistic conditions. And, if you want to adjust the volume in software, it’s best to have at least 110 dB DNR to keep the noise floor inaudible even if the downstream gain is left cranked way up. Anything beyond 110 dB is past the point of diminishing returns—it looks nice on paper but doesn’t help the sound quality......"
 
Fyi
A.

With respect - as a source, the signal doesn't stay at "-100dB" for very long.  It gets amplified.

 

[adydula]

We aren't talking about signal amplification, just the bottom floor that allows for dynamic range etc...push the device dynamic range into the inaudible area it doesn't matter range...the ODAC is there with 'dirty' USB power.
 
Adding other stuff to make this better it indeed subjective to me, IMO.
 
I have tried using pure DC, and a very expensive LAMDA DC regulated supply and I can not honestly hear any real world differences.
 
Its ok to have devices that make things "better" or go in the right direction, but with the ODAC they are really NOT needed.
 
That said its your choice......the ODAC's already stellar measurements were achieved with normal USB power across a variety of devices.
 
All the best
A.

 

[tomb]

  We aren't talking about signal amplification, just the bottom floor that allows for dynamic range etc...push the device dynamic range into the inaudible area it doesn't matter range...the ODAC is there with 'dirty' USB power.
 
Adding other stuff to make this better it indeed subjective to me, IMO.
 
I have tried using pure DC, and a very expensive LAMDA DC regulated supply and I can not honestly hear any real world differences.
 
Its ok to have devices that make things "better" or go in the right direction, but with the ODAC they are really NOT needed.
 
That said its your choice......the ODAC's already stellar measurements were achieved with normal USB power across a variety of devices.
 
All the best
A.

 
Inaudible where?  The measurements made from the perspective of the source - the initiation of the analog audio signal.  Any noise level introduced there is going to be amplified higher further down the audio string.  Just an FYI, but the common range of human hearing is reported as anywhere from 120 to 140dB (averages 130dB).  In any event, it's why you want a huge range/low noise on the source.

I just find it fascinating that certain aspects of objectivity are honored, while others are not.  With respect - saying now that improving the noise floor is not really necessary is just as bad as stating that distortion is inaudible at certain levels, too.  It's inconsistent.
 
Honestly, though, I'm not saying that anything is bad - just that there's a chance an improvement can be made.  So, we'll have to agree to disagree, I guess.

 

[adydula]

Yup we certaintly will have to disagree to some point in this regards, its great we can be civil though!! No harm meant or intended.
 
To me the ODAC has met all the criteria technically that provides a world class stellar DAC even on el crapo USB power.
 
For something to do that is simply amazing.
 
Good engineering at a very low cost in comparison to many other dacs out there.
 
Making devices that improve on the specs is great even if there is no objective audible improvement.
 
Improving on the noise floor is great but does it really do anything at all to the audible experience?
 
To me, after experimenting, it does not.
 
~~The dynamic range of human hearing is roughly 140 dB.[7][8] The dynamic range of music as normally perceived in a concert hall doesn't exceed 80 dB, and human speech is normally perceived over a range of about 40 dB.[9]
 
Most Redbook CD's don't exceed 96db and the real end result from CD with modern electronics is more like 90db.
 
The ODAC designed to be transparent based on the designers basis and specs and reasons for them. This is the important thing to me. What are the specs that need to be met to ensure a totally transparent device. It neither adds or takes away from the job at hand.
 
If you want a USB "cleaner" or better or cleaner USB power that's fine, it probably will not do anything to the actual audio but it may indeed do subjective wonders.......
 
All the best
A.

 

[fishski13]

the stock ODAC induced a headache within minutes 5min or less.  i don't have an O2 though.  the Doodlebug really did transform the DAC.  still not my flavor, but at least i could listen to it without pain.

 

[MaciekN]

Guys, come on. Just measure the ODAC with and without an external regulated linear power supply and be done with it. Then we can discuss how subjective impressions correlate with what is measured to have the full picture.
 
140 dB dynamic range... as far as I remember anything above 90 can cause permanent hearing damage, so saying that we must aim for 140 dB dynamic range in audio gear is like sacrificing your hearing for this one perfect track that would leave you deaf afterwards. Its good to have headroom, sure, but even that USB powered DAC mentioned earlier had enough headroom. Also, when it comes to headphones in many cases the signal NOT amplified, quite the contrary - most need less than redbook 2V to reach 90 or 100 dB. Of course, high impedance TOTL stuff needs more voltage but the gain we are talking about is like 3 dB? 6? Perhaps 10?
 
I general, (on measurement graphs) saying that all spikes are bad and no spikes is good is misinformation.
 
I am not denying anyone the right to post their purely subjective impressions, in the end that is what this community is about, but when discussing ODAC with its specific design goals its nice to use both electronics knowledge and subjective impressions, together. And not only to justify one with the other.

 

[DNICE1]

Guys, come on. Just measure the ODAC with and without an external regulated linear power supply and be done with it. Then we can discuss how subjective impressions correlate with what is measured to have the full picture.

+1

 

[Solrighal]

I just bought my ODAC XL & O2 yesterday. I have never heard this level of quality before. Awesome.

 

[jasonb]

congrats!

 

[jjacq]

Hello guys, thinking of buying the O2/ODAC but I'm wondering if it's anyone uses it with KRK Rokits or any active speakers? I also own headphones so I will most likely get a splitter but I want to know any input in how you guys set this up with active speakers.
 
*edit: ok I found my answer, use an ODAC to connect to active speakers. One follow up question would be if I can use the same ODAC with the O2 that will be used for headphone use?
 
So essentially it looks like this:
 
PC > ODAC > Speakers
PC > ODAC > O2 > Headphones
 
Do I need two ODACs to make this work? Or is there a way to not split the signal from the O2 to power speakers and headphones? I'd like to prevent double amping on the speakers if that's possible.
 
I'm assuming a 3-way male to male to male cable would work. 1 end would go to the ODAC the other end to the O2 and the other end to the speakers...?

 

[jasonb]

  Hello guys, thinking of buying the O2/ODAC but I'm wondering if it's anyone uses it with KRK Rokits or any active speakers? I also own headphones so I will most likely get a splitter but I want to know any input in how you guys set this up with active speakers.

It should work fine with active speakers, it should just plug right into the input on them. 
 
I use my ODAC with the aux input of my vintage Pioneer SX-750 along with some speakers and headphones. It's a great inexpensive DAC. 

 

[jasonb]

You can simply use a splitter or a switch. Either one will work. There is no need for two DAC's.

 

[MaciekN]

You would need a second set of outputs from eithr ODAC or O2. You could connect your ODAC to O2 and a speaker amp by simply soldering the wires to both output jack and RCAs but thats suboptimal, it would be best to have only one source connected at a time (consider soldering a switch, or putting a passive preamp between any amps and ODAC). Second option is to get an O2 with RCAs on the back and a headphone jack with an integrated switch that enables RCAs only when the headphones are plugged out. Or just attach a splitter at O2 headphone out, speaker amp's high input impedance shouldn't make any difference to O2's output stage as it would be headphones with their relatively (compared to speaker amp) low impedance that would determine power requirements. Be careful though, because in this case you may get more than the usual 2V at speaker amp's input (worst case even 6-7 volts), so keep the volume low on your speakers.